1. Field of the Invention
The present invention relates to a master, a pixel array substrate, an electro-optical device, and methods of manufacturing the said elements. More particularly, the present invention relates to a master having an electrostatic discharge (ESD) protection structure, a pixel array substrate, an electro-optical device, and methods of manufacturing the said elements.
2. Description of Related Art
An ESD phenomenon is quite common in our daily lives. Since various objects are of different electron affinities, charge-transferring reactions are likely to be generated when any two objects are brought into contact and then separated, thus leading to an accumulation of electrostatic charges. As long as the electrostatic charges in the objects are accumulated to a certain degree, a sudden and momentary electric current flows between the two objects occurs when one of the objects carrying the electrostatic charges is in contact with or approaching to the other object at a different electrical potential, leading to an ESD event.
A liquid crystal display (LCD) panel is herein taken for an example. During processes of manufacturing, producing, assembling, delivering, and using the LCD panel, the LCD panel is very much likely to suffer the ESD damage. Therefore, the LCD panel must be equipped with a design of preventing the ESD damage, such that the lifetime of the LCD panel is effectively extended. In general, the LCD panel includes a pixel array substrate, an opposite substrate, and a liquid crystal layer disposed therebetween. Here, the fabrication of the pixel array substrate is taken for an example. In order to improve the manufacturing efficiency, a plurality of displaying units is often formed on a master of a glass substrate. Thereafter, through an implementation of a cutting process, the displaying units are cut off, so as to form a plurality of pixel array substrates.
In addition, during the formation of the displaying units, an ESD protection circuit characterized by satisfactory conductivity can be formed on the glass substrate for connecting each of the displaying units. The ESD protection circuit is capable of conducting the electrostatic charges out of the displaying units, given that the accumulation of the electrostatic charges takes place in any step of the manufacturing process, so as to avoid circuits or elements in each of the displaying units from suffering the permanent ESD damage. Further, after the displaying units are cut off and a plurality of the pixel array substrates is formed, the ESD protection circuit is also conducive to releasing the electrostatic charges possibly generated during the assembling process, the delivering process, or even after consumers purchasing the LCD panels start using the same. Accordingly, a disposition of the ESD protection circuit results in an extension of the lifetime of the LCD panel to which the pixel array substrate is applied.
However, when the displaying units are cut off and the plurality of the pixel array substrates is formed, the ESD protection circuit made of a metallic material is exposed, wherein the metallic material within non-transparent function consists of Au, Ag, Al, Sn, Cu, Ti, Ta, Mo, W, Nd, or others, or alloy thereof. In subsequent processes of inspecting the panel, the exposed metal may be corroded or oxidized, further posing a negative impact on display performance of the LCD panel. In light of the foregoing, the conventional LCD panel cannot simultaneously achieve favorable display performance and maintain the lifetime of the LCD panel.